1. Field of the Invention
The present invention relates to an apparatus for mounting electronic components or the like on a substrate by means of suction nozzles and attaching the same exactly at proper positions without causing any load to the substrate or the electronic components either.
2. Description of the Prior Art
Relative to the conventional apparatus designed for automatically mounting electronic components on the surface of a circuit substrate or the like, there is known a type called a chip placer. Generally such chip placer picks up an electronic component fed from a parts cassette while sucking it by means of a suction nozzle and then mounts the same at a predetermined position on a circuit substrate.
If any skew or distortion is existent in the substrate for mounting electronic components, there arises a problem that each electronic component fails to be accurately mounted at a proper position on the substrate by the suction nozzle. Particularly in any of the latest products where the packaging density on the circuit substrate has been enhanced, it is a matter of importance to realize exact mounting of electronic components at accurate positions on the substrate.
In view of such circumstances, there is proposed a contrivance as illustrated in FIG. 6 for the purpose of precisely mounting electronic components on a substrate despite its skew or distortion, wherein a spring 51 is fitted into a fore end of a suction nozzle 50, and a component sucking portion 52 formed at the fore end is moved upward or downward in compliance with the skew of the substrate K to thereby absorb such skew, hence enabling proper attachment of the electronic component onto the substrate K.
However, according to the means mentioned above, the electronic component T to be mounted is pressed against the substrate K to be consequently affected by an excessive force. As a result, in case any great skew or the like is existent, some impact may be imparted to the electronic component to eventually cause crack or flaw in the component itself. And in a worse case, the substrate K may also be damaged.
Furthermore, in the mounting stage, there may arise another problem that the substrate K is vibrated to induce a positional error of each component already mounted.
One of the known means contrived for solving the above problems is such as shown in FIG. 7, wherein a substrate K supported in a substrate holder 60 is sucked by vacuum means in the holder 60 so that any skew or the like of the substrate K is corrected forcibly, and then an electronic component T is mounted on the surface of the substrate. According to this means, any skew or the like of the substrate K can be eliminated with certainty to achieve proper mounting of the electronic component at the accurate position on the substrate surface without giving any excessive load to the component.
In employment of such means, however, it is necessary to provide a suction jig 61 which conforms with the substrate K for attaining exact suction of the substrate K in the holder 60. Therefore a disadvantage is unavoidable with respect to both the general-purpose usability and the production cost, so that such means is not adoptable practically. In addition, some restriction is also non-negligible in designing the substrate K since a complicated structure thereof is not permitted due to the necessity of exact suction of the substrate K by the suction jig 61.